G. W. SALISBURY and C. N. GRAVES

Summary.

A technique is presented for the collection of ejaculated bovine spermatozoa directly into an inhibitory diluent which renders the cells immotile and prevents the absorption of carbohydrate from the seminal plasma. When removed from the inhibitory diluent, such cells have low endogenous respiration which is markedly increased by the addition of fructose to the incubation medium or by pre-incubation in a fructose solution before washing and then subjecting the cells to a period of endogenous respiration. After storage at 5° C for 24 hr in the collection medium, and after their subsequent removal from the inhibitory medium, the endogenous respiration rate of such spermatozoa and their respiration in the presence of fructose is greater than the initial respiration level. All these responses are typical of bovine epididymal spermatozoa.

G. W. SALISBURY and J. R. LODGE

Summary.

The oxygen consumption of sixteen samples of ejaculated bovine spermatozoa in diluted semen was more rapid in the presence of the respired carbon dioxide than it was for similar spermatozoa respiring in the presence of alkali to absorb the evolved carbon dioxide. Thus, respiratory quotients for seminal spermatozoa calculated from oxygen consumptions obtained by the direct method of Warburg, in the absence of respired carbon dioxide, are in error, being larger than is characteristic of the substrate oxidized.

The oxygen consumption of seventeen samples of ejaculated bovine spermatozoa washed free from seminal plasma was not influenced to the same degree by the absence of the respired carbon dioxide. However, the influence was sufficient to question the accuracy of the direct method of Warburg for measuring respiratory quotients for bovine spermatozoa.

C. N. GRAVES and G. W. SALISBURY

Summary.

The ability of bovine spermatozoa to metabolize carbohydrates and other compounds oxidatively has been studied, using spermatozoa free of the components of the seminal fluids. Only glucose, fructose, mannose and galactose of the hexoses were significantly oxidized by the spermatozoa.

R. BOUTERS, C. ESNAULT, G. W. SALISBURY and R. ORTAVANT

Summary.

The dna content of individual ejaculated spermatozoa and of spermatozoa recovered from the epididymis and ampulla of fifteen rabbits was measured by means of two microspectrophotometric methods: (i) direct determination of ultra-violet (uv) light absorbed at 260 mμ by unstained spermatozoa, and (ii) determination of visible light absorbed at 560 mμ by Feulgen-stained spermatozoa. The dna determinations in uv light for ejaculated spermatozoa and for those recovered from the male ducts revealed no difference, as contrasted with the results obtained by measuring the Feulgen-stainability. The differences in Feulgen-stainability, i.e. in the quantitative response of spermatozoa to the Feulgen reagent, are attributed to an ageing process in the sperm cells: ampullary spermatozoa yielded significantly lower Feulgen-dna values than those obtained from the epididymis; ligation of the vas deferens resulted in a decrease of the Feulgen-dna content of epididymal spermatozoa; the variable Feulgen-dna content of individual ejaculated spermatozoa is attributed to varying percentages of older sperm cells in the ejaculates.

G. W. SALISBURY, C. N. GRAVES, N. T. NAKABAYASHI and R. G. CRAGLE

Summary.

This study was conducted to determine the effect of added sulphur compounds, substrates and various inorganic ions on the metabolic activity of epididymal spermatozoa from twenty-one bulls and five goats. The addition of sulphur at physiological levels in the form of sulphide, sulphite, sulphate and glutathione in several different media caused no stimulation of respiration. An apparent stimulation of oxygen uptake by the addition of cysteine was shown to be due to auto-oxidation of the added cystein. Calcium and magnesium in a Ringerphosphate medium had no obvious effect on metabolism, while phosphate decreased oxygen uptake but increased glycolysis and lactate accumulation in the presence of substrate. Substrate, present even for a short period of time before removal, stimulated metabolism markedly during the subsequent incubation period.

K. K. MITTAL, G. W. SALISBURY, C. N. GRAVES and B. A. RASMUSEN

Summary.

Bull semen is very strongly antigenic in rabbits. At least twenty antigenic components were detected by micro-immunoelectrophoresis.

There was a drastic reduction in oxygen uptake, fructose utilization and lactic acid production by bull spermatozoa when mixed with specific antisemen serum. This decreased metabolic activity in the presence of the antisemen was due to death of the spermatozoa as indicated by the live-dead staining technique.